Ammunition | Firearms
How to Make Subsonic Ammo Cycle in your AR 15

How to Make Subsonic Ammo Cycle in your AR 15

How to Make Subsonic Ammo Cycle in your AR 15

Running an AR-15 with a suppressor is a lot of fun and it’s definitely quieter than an unsurpassed AR-15, but it isn’t anything like the movies. (Hollywood ruins everything.) You can, however, quiet things down even more by pairing your AR-15 with subsonic ammo.

This can lead to some complications, but they’re easy to solve. First, let’s explain why there can be issues.

An AR-15 uses the gases from each fired round to cycle the action on the gun and prepare it for the next round. A suppressor changes how those gases interact with the gas system in the gun, and the reduced speed of subsonic ammo also impacts the gas in the system.

This means that in some cases, you might find that your AR-15 either isn’t cycling properly or isn’t cycling at all with subsonic ammo – especially when paired with a suppressor. Fret not, we can fix it!

Why Use Subsonic Ammo for Your AR?

But if the pairing of subsonic ammo with an AR-15 can cause cycling and reliability issues, why use it at all? So glad you asked…

Sound Reduction

Suppressors are great at bringing down decibel levels, but they can’t do anything about the supersonic crack that is created when a bullet breaks the sound barrier. Supersonic rounds travel slower than the speed of sound, so you don’t get that loud crack. When you pair subsonic rounds with a suppressor, you’re getting the quietest combination possible from an AR-15.

Why Your Subsonic Ammo Isn’t Cycling in your AR-15

As we mentioned above, there are a number of things that can lead to cycling issues with subsonic ammo in an AR-15. Let’s take a look at some of the most common ones.

Not Enough Chamber Pressure

We talked about how gas pressure ensures the proper operation of the AR-15. Without sufficient chamber pressure, there won’t be enough force behind the gas as it goes into the gas tube to cycle the action properly. Evidence of not enough chamber pressure can be that your action isn’t cycling completely and is failing to fully extract the spent case or chamber the next round. Or, it can be seen if an action fails to cycle at all, leaving the spent case in the chamber.

Your Gun isn’t Designed for it

No gun comes out of the box ready to cycle any and every different load option on the market. You no doubt have experienced this with different brands of ammo, different powder charges, or different bullet weights.

All of those variables impact how the different stock parts of your AR-15 function, and not all of those parts are designed to provide peak performance with subsonic ammo.

How to Make Subsonic Ammo Cycle in an AR-15

Because of the exceptional modularity of the AR-15, it’s really easy to swap out and switch around parts from what came in the gun from the factory to aftermarket options that play nicer with subsonic rounds. Here are some of the things you can do.

Use a Lighter Buffer

The reduced gas pressure from subsonic rounds can make it harder for your firearm to push the bolt carrier group and the buffer rearward, which is what needs to happen in order to eject the spent casing and load the next round. Using a lighter buffer can make it easier for the bolt carrier group to push the buffer to the back.

Use a Lighter Spring

In addition to lighter buffers, you can also use lighter buffer springs. This works in a similar way to the lighter buffer. Whereas a lighter buffer means less mass to be moved rearward, a lighter buffer spring means less compression resistance to move the bolt carrier group and buffer back for the action to cycle.

Attach a Suppressor

Suppressors are one of the most fun aspects of running subsonic ammo in an AR-15, and because they pair well together, using a suppressor can help mitigate some of the issues you might be having. Pairing a suppressor with the next option on the list is a really great thing to do, too, and we highly recommend it if you’re going to be shooting subsonic ammo with a suppressor.

Install an Adjustable Gas Block

Again, it all comes down to gas pressure. With an adjustable gas block, you can fine-tune the amount of gas that is bled off of the rifle into the gas tube and the amount of gas that is expelled as excess from the rifle.

If you need more gas pressure to cycle the action, you can adjust the opening in the gas block to channel more gas back into the action. It allows you to achieve a “Goldilocks” scenario, where the amount of gas cycling the action isn’t too much or too little – it’s just right for subsonic ammo.

Cycle Subsonic Ammo Reliably

It can certainly be frustrating when you load up some new subsonic ammo, head to the range, and find out that your AR-15 isn’t cycling properly. Thankfully, the ways to fix this issue are fairly simple to do and are, for the most part, fairly inexpensive, too.

With a few new parts and/or some careful adjustments, you can get your AR-15 dialed in perfectly so that it cycles subsonic ammo with absolute ease. When you get your gun to that point, you will be able to enjoy some of the benefits of using subsonic ammo in your AR-15.

Of course, to enjoy all of the benefits of subsonic ammo in an AR-15, you’re going to need a suppressor. When you’re ready to take that next step, Silencer Central is here to help. We’ve made the process incredibly simple, allowing you to complete the entire purchase from the comfort of your own home. Then, when the ATF approves your purchase, we’ll mail it right to your front door. It doesn’t get any better than that!